How to setup VPN connection?

First and foremost, please enable L2TP over IPSec, and setup Username/password/PSK to vpn/vpn/11111111, respectively:

1.Windows client:Step 1: Initial configurations (only once at the first time): Right-click the network icon on the bottom-right side of Windows screen, and click "Open Network and Sharing Center".Step 2: Click "Set up a new connection or network" on the "Network Sharing Center":

Step 3: Select "Connect to a workplace":

Step 4: Select "Use my Internet connection (VPN)":

Step 5: You have to input the destination SoftEther VPN Server's IP address or hostname here:
Enter either hostname or IP address on the "Internet address" field on the configuration wizard.

Step 6: Type your username and password you set on the router:

Step 7: When "The connection is ready to use" message appears, click the "Close" button. Do not click the "Connect now" button.

Step 9: The currently defined VPN connection settings are listed. Right click the icon you created in the previous step, and click "Properties":

Step 10: On the Properties screen, switch to the "Security" tab. (In Windows XP, switch to the "Network" tab.) Choose "Layer 2 Tunneling Protocol with IPsec (L2TP/IPSec)" on the "Type of VPN" drop-down list.
The following screen will appear. Click "Use preshared key for authentication" and input the pre-shared key on the "Key" field.

Step 11: Connect to the VPN Server: Double-click the created VPN connection setting, the below screen will appear. "User name" and "Password" fields should be filled automatically if you enable password-saving options in previous steps. If not, input both "User name" and "Password" fields.
Click the "Connect" button to start the VPN connecting attempts.

Step 12: If the VPN connection is successfully established, a VPN connection icon will be listed on the screen which appears when you click the network icon on the bottom-right of Windows screen. The status of the VPN connection icon should be "Connected".

2.Mobile client (Android):Step 1: Add new VPN profile:

Step 2: Edit the name of VPN connection and select VPN type as L2TP/IPSec PSK: